This invention relates generally to bedding or seating products, and more particularly to a box spring bedding product made with plastic spring modules in lieu of coil springs.
A conventional box spring comprises a generally rectangular wooden frame, and a generally rectangular wire grid spaced above the wooden frame with a plurality of coil springs. Lower end turns of the coil springs are stapled or otherwise secured to side and end rails of the wooden box spring frame as well as interior rails extending either transversely between the side rails or longitudinally between the end rails (from head to foot). Similarly, the upper end turns of the coil springs are secured to the wire members of the wire grid in any number of ways.
Several patents disclose box springs utilizing springs other than coil springs to space the upper wire grid from the lower wooden frame. For example, U.S. Pat. No. 5,720,471 discloses generally C-shaped spring modules extending between the upper wire grid and a wooden base. This patent also discloses spring modules of differing shapes, such as spring modules having an S-shaped cross-section or a U-shaped cross-section.
However, none of the configurations of spring modules disclosed in U.S. Pat. No. 5,720,471 are configured such that the spring modules may be preassembled to wire grids and shipped to a bedding manufacturer with the spring modules nestably stacked inside one another to conserve space for shipping purposes.
Conventional box spring assemblies occupy a large volume and thus are costly to ship and store in an assembled condition. In order to reduce the space requirements for shipping mattresses, it is customary to compress mattress spring assemblies to reduce their individual thicknesses and to tie them in a compressed state into bales. This compression and shipping process is possible with mattress spring assemblies but is not possible with box spring assemblies because of their lack of compressibility.
Consequently, box spring assemblies which may be preassembled and densely packaged for shipment to a bedding manufacturer are desirable. Such box spring assemblies are known. For example, applicants"" own U.S. Pat. No. 5,361,434 discloses a nestably stackable foundation assembly which may be nestably stacked with other similar assemblies for transportation, thereby minimizing shipment costs. As disclosed in this patent, the wooden bases of the box springs, and the nestable, stackable spring foundation assemblies are stacked and shipped separately. At the bedding manufacturers destination, the spring manufacturer assembles the components together into a box spring foundation before upholstering the foundation into a finished bedding product.
Therefore, it has been one objective of the present invention to provide a bedding foundation having molded plastic spring module components which may be attached to a wire grid and nestably stacked for shipping, thereby minimizing shipment costs and maximizing ease of assembly and completion of the upholstered box spring by the bedding manufacturer.
Another object of the present invention has been to provide a bedding foundation which is relatively simple to manufacture and which may substitute for a traditional box spring assembly having coil springs extending between an upper wire grid and a lower wooden-base.
The invention of this application which accomplishes these objectives comprises a bedding or seating product having a wire grid spaced above a base and a plurality of modules extending between the base and wire grid. Each of the modules comprises a bottom portion adapted to be joined to the base and four arms extending upwardly from the bottom portion. Each of the arms terminates in an end portion having a pair of grooves adapted to receive intersecting wires of the wire grid.
The base is generally wooden but may be made of other materials, such as aluminum struts or foam plastic rails, or combination thereof. The base includes a frame comprising a pair of longitudinally extending side rails, a pair of transversely extending end rails and a plurality of parallel spaced internal rails extending either transversely between the side rails or longitudinally between the end rails.
The wire grid comprises a generally rectangular border wire and a plurality of intersecting transverse and longitudinal wires. The transverse wires extend from side-to-side, and the longitudinal wires extend from end-to-end. The longitudinal and transverse wires are preferably welded or otherwise secured together at their intersections in order to create a unitary wire grid.
The modules of the present invention are preferably made of plastic, but may be made of other materials as well. The modules are nestably stackable inside one another in order to conserve space during shipping. Each of the modules comprises four arms which extend upwardly from a bottom portion of the module, each arm terminating in an end portion. Each end portion has two grooves extending generally perpendicular to one another. One of the grooves is adapted to receive one of the transverse wires of the wire grid, and one of the grooves is adapted to receive one of the longitudinal wires of the grid.
In one of the embodiments of the present invention, each of the modules has a stabilizer bar extending between adjacent arms of the module. The stabilizer bars provide stability and make the module arms less prone to breaking or otherwise being damaged upon excessive overloading of the modules.
These and other objects and advantages of the present invention will be more readily apparent from the following description of the drawings.